Fuses are used extensively in high voltage electrical networks in order to protect the electrical equipment in the network from damage caused by surges through the system, generally occasioned by short-circuits or overloads. It does occur that a very temporary surge will have the effect of causing a fuse to blow under circumstances in which the cause of the temporary surge is unlikely to repeat itself soon, if ever. In the absence of a fuse holder assembly that can automatically connect to a second, and possibly subsequently a third fuse connected into the electrical power supply circuit in parallel, the consumers supplied through that particular circuit will be subjected to a power interruption that can be extremely inconvenient and often harmful. Also, the labour and cost involved in replacing a fuse is generally considerable.
As an answer to this problem U.S. Pat. No. 5,796,326 to Derick Benito and its counterparts including South African patent number 96/2576, describe a fuse holder assembly in which, in the described preferred form of the invention, a carrier for a plurality of fuses is rotatably mounted relative to contacts in the circuit so that a second, and thereafter a third fuse will be connected into an electrical supply circuit sequentially in the event that the first or second fuse blows as the case may be. This earlier patent also describes a fuse holder in which a rotatable arm is employed to firstly connect with a first stationary fuse and thereafter with a second stationary fuse and optionally also subsequently a third stationary fuse.
Whilst these fuse assemblies operate effectively from a mechanical point of view, in at least some applications, particularly those involving high voltages, there is a need for the assembly to include means for ensuring that a blown fuse is properly cleared, and the inevitable arc that occurs when a fuse blows, has died down adequately, before the next fuse is connected into the circuit as a replacement.